Slack adjuster



T. JAMES, JR

SLACK ADJUSTER Filed June 5, 1956 2 Sheets-Sheet 1 .2 9% w mw. w Q, mmevm 1m J mn a h? MR. Sm 3 Q y 1938. T. JAMES, JR I 2,117,250

' SLACK ADJUSTER Filed June 5, 19556 2 Sheets-Sheet 2 Patented May 10, 1938 UNITED STATES aliases PATENT DFFiCiE SLACK ADJUSTER Application June 5,

6 Claims.

My invention relates to improvements in automatic slack adjusters for standard brake rigging for railway cars.

, The object of my invention is to provide a slack adjuster which may be installed in any standard brake rigging without the necessity of changing or eliminating parts of the brake rigging now in use.

A further object is to provide a slack adjuster which may be associated with any of the various connections of the brake rigging where a brake rod having a jaw, or bifurcated head, is pivotally connected with a lever. A further object is to provide a slack adjuster "comprising means upon a lever, or brake beam, for adjustably engaging racks secured to the head of a standard brake rod and the rocking movement of the lever relatively to the rod will automatically advance the pivot point between the lever and the rod for taking up the slack in the rigging.

A further object is to provide means for preventing the accidental movement of the rod relatively to the lever when the brakes are released and the parts are subjected to the shaking of the car and particularly to end thrusts to which the car is subjected.

A further object is to construct the slack adjuster of members which may be manufactured at a low cost, and which may be quickly attached to the rigging, and also to construct said members in a substantial manner so that they will withstand the great strains to which they are subjected.

These together with various other novel features of construction and arrangement of the parts, which will be more fully hereinafter ,.de scribed and claimed, constitute my invention.

Referring to the accompanying drawings:

40 Fig. 1 is a side elevation of my novel slack adjuster and showing one means for installing the same in a brake rigging.

Fig. 2 is an end view of the slack adjuster shown in Fig. 1.

Fig. 3 is a longitudinal section on line 33 Fig. 2, and showing the lever in brake applying position.

Fig. 4 is a horizontal section on line 4-4 Fig. 3.

Fig. 5 is a horizontal section on line 5-5 Fig. 3.

Fig. 6 is a partial longitudinal section as on line 6-6 Fig. 2 showing the lever in the position shown in Fig. 1.

Fig. '7 is a perspective view of the adjusting pawl, detached.

1936, Serial No. 83,631

Fig. 8 is a perspective View of the holding pawl, detached.

In the drawings, in which like reference characters refer to like parts, Ill represents a pull rod connected With a lever E2 of the type in general use in standard brake rigging and shown in Fig. l. The lever l2 is operated by said pull rod ill by means of an air brake cylinder not shown in the drawings. A similar lever l3is pivoted upon a link which in turn is pivoted upon a fixed bearing 54. The opposite ends of the lever l2 and i3 are pivotally connected through a brake rod l5. Brake shoes I! and I8 are associated with the intermediate portions of the levers and are movable into engagement with the wheels 23, indicated by dot and dash lines.

The part I5 is the standard brake rod having bifurcated heads 22 and 23, adapted to receive one end of a lever, such as the lever l3, which is pivotally connected to the head by a pin 25. Said heads are each usually provided with three holes 26 for adjustingthe rigging manually by changing the position of a pin 25.

My novel slack adjuster 30 comprises a block 3% adapted to be inserted between the jaws of the head 22, of the push rod l5. The block 3! has transverse holes 32 and 33 to receive pins 35 and 35, similar to the pin 25, for rigidly securing said block within the bifurcated head 22, as shown in Fig. 3.

The block 3| extends above the top surface of the jaws of the head 22 and the top surface of the block is provided with teeth 38 forming a rack 39, extending longitudinally relatively to the rod 55.

Cheek plates 40 and ll are positioned upon the outside surfaces of the jaws of the head 22. Said plates are each provided with holes 52 and 43 which are occupied by the pins 34 and 35 for rigidly securing said plates upon the head.

The hole 32 in the block 3|, and the holes 42 in the cheek plates 40 and 4|, are elongated to provide for variations in the location of the holes 26 formed through the head 22, and also to permit the block 3| and said cheek plates to be moved, for increasing the effective length of the rod l5,

- by removing the bolt 35, sliding said block and cheek plates upon the bolt 34, and inserting the bolt 35thr0ugh the center one of the three holes 26 formed through the head 22 of the rod.

The cheek plates 40 and M are each provided with teeth 45 forming racks 45 along the top edges ofsaid plates. Said racks 46 extend parallel with the rack 39. The cheek plates All and 4| are each provided with an elongated slot 48 .defined by guides 49 to receive a cross-head 56,

which may be in the form of a pin, mounted upon the lever I2. Said cross-head 59 forms a pivotal axis about which the lever I2 reciprocates.

A holding pawl 52 shown detached in Fig. 8, is pivotally mounted upon the cross-head 50, and is adapted to engage the rack 39, of the block 3|, and impart rectilinear motion to the rod I5, in the direction 'of the arrow Fig. 1, when the lever I2 is operated for applying the brakes.

The holding pawl 52 comprises collars 53 and 54 connected by a bar 55 having a rack engaging edge 58 thereon. The collars 53 and 54 embrace the lever I2 between them.

An adjusting pawl 58 is also pivotally mounted upon the lever I2 by means of a pivot pin 88. The pawl 58 comprises two collars 5! and 62 which embrace the lever I2. Said collars are connected by a bar 53 having a rack engaging edge 64 for engaging the racks 45 of the cheek plates 40 and 3E.

The teeth 45 of the racks 45 are the proper distance apart so that the pawl 58 rides back and forth over the inclined surface of a tooth 45 during the normal strokes of the lever I2 for operating the brakes, as shown in the relative positions of the lever I2 in Figs. 3 and 6. When the lever I2 exceeds its normal stroke, due to wear of the brake shoes or slack in the rigging, the adjusting pawl 58 will engage a new tooth 45.

After said pawl 58 has dropped into a new tooth 45 and upon the return stroke of the lever I2, said pawl 58 will act as a fulcrum and cause the cross-head 58 to move within the guides 49 so that the holding pawl 52 will engage a new tooth 38 of the rack 39 on the block 3I and thereby increase the effective length of the rod 5 for taking up slack in the rigging.

The accidental movement of the rod I5 relatively to the lever I2 is prevented by means of lugs 55 formed upon the pawl 52 which are adapted to engage lugs 66 formed upon the pawl 58, as shown in Fig. 6 for preventing the pawls from withdrawing from the teeth 38 or 45 when force is applied to the rod I5 tending to move it in the direction of the arrow, Fig. 1. When the lever I2 rocks about the'cross-head 5D for moving the rod I5 in the direction of the arrow, by means of the holding pawl 52, the lugs 55 and 66 will separate sufficiently to allow the pawls to be alternately moved to engage new teeth when the lever I2 reciprocates for operating the brakes, as clearly shown in Figs. 3 and 6.

The lugs 65 and 65 are provided with recesses 68 and 69 which are occupied by spring 18, as clearly shown in Fig. 6. Said spring 18 prevents the accidental withdrawal of the pawls from the teeth of the racks 38 and 45.

The operation of my invention is as follows: lThe lever I2 moves from the released position shown in Figs. 1 and 6, to the position shown in Fig. 3 during the normal strokes of the lever for applying the brakes. The normal stroke of the lever I 2 will cause the pawl 58 to ride upon a tooth 45 from the position shown in Fig. 6 to the position shown in Fig. 3, and the holding pawl 52 will move the push rod I5 in the direction of the arrow Fig. 1, for applying the brakes. When the lever I2 exceeds its normal stroke, due to slack in the rigging, the adjusting pawl 58 will engage a new tooth 45 when the lever I2 is moved to brake applying position, as shown in Fig. 3. The return movement of the lever I2 to the released position shown in Fig. 6 will cause the cross-head 5D to move within the guides 49, due to the pawl .58 acting as a fulcrum, and the pawl 52 will engage a new tooth 38 in the block 3| secured upon the push rod I5.

The lugs and 85 upon the pawls will move apart when the lever I2 is moved to apply the brakes as shown in Fig. 3 and the pawls may engage new teeth, but when the lever I2 is not in brake applying position the lugs 65 and 66 of the pawls will engage each other so that the pawls cannot be withdrawn from the teeth 38 or 45 of the racks, thereby preventing any movement of the rod I5 in the direction of the arrow Fig. 1, thus preventing any accidental movement of the rod I5 in relation to the lever I2 when the brakes are in the released position. A spring I5 positioned between the lugs 65 and 66 tends to hold the pawls in engagement with the racks at all times.

Various changes in the arrangement of the parts and the details of construction may be made without departing from my invention.

I claim:---

1. A slack adjuster for brake rigging for a railway car comprising a rod associated with the rigging, a lever associated with the rod and having a normal stroke for operating the brakes, a guide upon the rod, a cross-head mounted upon the lever and slidably mounted upon said guide, means operatively associated with the cross-head and engageable with said rod for resisting movement of the cross-head in one direction, a pivot pin upon the lever and positioned for rotary movement about the cross-head as an axis, an adjusting rack having teeth thereon and associated with one end of the rod, a pawl pivotally mounted upon said pivot pin and adapted to reciprocate over one of said teeth during the normal strokes of the lever and for .engaging a new tooth upon an excessive stroke of the lever, said pawl arranged to form a fulcrum for the lever when so engaged with said new tooth and for advancing the cross-head to a new position upon I the guide for taking up slack in the rigging, means controlled by the position of the lever and operatively associated with said pawl for locking the latter with said teeth when the lever is in the brake released position for'pre'venting. movement in either direction of said rod relatively to the lever, and said last mentioned means arranged for unlocking the pawl relatively to-the teeth by a movement of the lever toward brake application position.

2. A slack adjuster for brake rigging for a railway car comprising a rod associated with the rigging, a lever associated with the rod and having a normal stroke for operating the brakes, a guide upon the rod, a cross-head mounted upon the lever and slidably mounted upon said guide, 1

means operatively associated with the cross-head and engageable with said rod for resisting movementof the cross-head in one direction, a pivot pin upon the lever and positionedfor rotary movement about the cross-head as an axis, an adjusting rack having teeth thereon andassociated with one end of the rod, a pawl pivotally mounted upon said pivot pin and adapted to reciprocate over one of said teeth during the normal strokes of the lever and for engaging a. new tooth upon an excessive stroke of the lever, said pawl arranged to form a fulcrum for the lever when so engaged with said new tooth and for advancing the cross-head to a new position upon the guide for taking up slack in the rigging, and a lug upon said pawl adapted to engage a part fixed relatively to the rod when the lever is in brake release position and lock the pawl in engagement with the rod and hold the rod against movement in either direction relatively to the lever.

3. A slack adjuster for brake rigging for a railway car comprising a rod adapted to be reciprocated longitudinally, a lever associated with the rod and having a normal stroke for operating the brakes, a guide upon the rod, a crosshead slidably mounted in said guide, means mounting one end of the lever upon the crosshead as a pivotal axis, a holding pawl pivotally mounted upon the cross-head, a rack upon the rod and engaged by said pawl and arranged for moving the rod in one direction for applying the brakes, a pivot pin positioned upon the lever for rotation with the lever about the cross-head as a pivotal axis, an adjusting pawl pivotally mounted upon said pin, a rack having teeth thereon and engaged by said adjusting pawl and adapted for advancing the cross-head within the guide, and lugs upon said pawls positioned to take against each other when the lever is in brake release position and lock the pawls relatively to said racks.

4. A slack adjuster for brake rigging for a railway car comprising a rod associated with the rigging, a bifurcated head upon the rod, a block located within said head, cheek plates located upon opposite sides of said head, transverse pins extending through said head and arranged for securing said block and said plates upon the head, guides upon the cheek plates defining slots extending parallel with the length of the rod, a lever having a predetermined stroke for operating the brakes, a cross-head mounted upon one end of the lever and slidably mounted within said guides, a holding pawl pivotally mounted upon the cross-head, a rack upon said block and engaged by said pawl, a pivot pin positioned upon the lever for rotation with the lever about the cross-head as a pivotal axis, a rack upon a cheek plate, and an adjusting pawl pivotally mounted upon said last mentioned pin and engaging the last mentioned rack.

5. A slack adjuster for brake rigging for a railway car comprising a rod associated with the rigging, a bifurcated head upon the rod, a block located within said head, cheek plates located upon opposite sides of said head, transverse pins extending through said head and arranged for securing said block and said plates upon the head, guides upon the cheek plates defining slots extending parallel With the length of the rod, a lever having a predetermined stroke for operating the brakes, a cross-head mounted upon one end of the lever and slidably mounted within said guides, a holding pawl pivotally mounted upon the cross-head, a rack upon said block and engaged by said pawl, a pivot pin positioned upon the lever for rotation with the lever about the cross-head as a pivotal axis, a rack upon a cheek plate, an adjusting pawl upon said last mentioned pin and engaging the last mentioned rack, said pawls arranged to advance the crosshead within said slot upon an abnormal stroke of the lever for increasing the effective length of the rod relatively to the lever, and locking means associated with a pawl and arranged for locking the pawl relatively to a rack when the lever is in brake release position.

6. A slack adjuster for brake rigging for a railway car comprising a rod associated with the rigging, a bifurcated head upon the rod, a block located within said head, cheek plates located upon opposite sides of said head, transverse pins extending through said head and arranged for securing said block and said plates upon the head, guides upon the cheek plates defining slots extending parallel with the length of the rod, a lever having a predetermined stroke for operating the brakes, a cross-head mounted upon one end of the lever and slidably mounted within said guides, a holding pawl pivotally mounted upon the cross-head, a rack upon said block and engaged by said pawl, a pivot pin positioned upon the lever for rotation with the lever about the cross-head as a pivotal axis, a rack upon a cheek plate, an adjusting pawl upon said last mentioned pin and engaging the last mentioned rack, said pawls arranged to advance the crosshead within said slot upon an abnormal stroke of the lever for increasing the effective length of the rod relatively to the lever, lugs upon said pawls positioned to take against each other in one position of the lever and lock the rod against accidental movement relatively to the lever, and a. spring positioned between said lugs and tending to engage the pawls with said racks.

THOMAS JAMES, JB. 

